Re: [RFC 1/2] IMAGE_ROOTFS_SIZE Cleanup

[Darren Hart <dvhart@linux.intel.com>]

On 05/26/2011 12:54 PM, Joshua Lock wrote:
> On Thu, 2011-05-26 at 11:28 -0700, Saul Wold wrote:
>> On 05/26/2011 11:04 AM, Joshua Lock wrote:
>>> On Mon, 2011-05-23 at 23:38 -0700, Saul Wold wrote:
>>>> This basic cleanup removes the _ext2/3 overrides from places they
>>>> no longer belong since they did not allow further overrides. In doing
>>>> this the core-image-minimal* recipes can now set a reasonably small
>>>> rootfs so that it's a realistic size for minimal.
>>>
>>> Awesome. Thanks for tackling this!
>>>
>>> Few questions below.
>>>
>>>>
>>>> The new default for minimal is 8M and will be adujsted upward by the
>>>> IMAGE_OVERHEAD_FACTOR (of 1.2).
>>>>
>>>> This fixes the ROOTFS_SIZE usage in the IMAGE_CMD_<fstype>  code
>>>>
>>>> Signed-off-by: Saul Wold<sgw@linux.intel.com>
>>>> ---
>>>>   meta/classes/image_types.bbclass                   |    7 +++++--
>>>>   meta/conf/distro/include/default-distrovars.inc    |    2 --
>>>>   meta/conf/machine/include/qemu.inc                 |    2 --
>>>>   .../images/core-image-minimal-initramfs.bb         |    2 ++
>>>>   meta/recipes-core/images/core-image-minimal.bb     |    2 ++
>>>>   5 files changed, 9 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/meta/classes/image_types.bbclass b/meta/classes/image_types.bbclass
>>>> index ec0cafd..69f859e 100644
>>>> --- a/meta/classes/image_types.bbclass
>>>> +++ b/meta/classes/image_types.bbclass
>>>> @@ -21,22 +21,25 @@ runimagecmd () {
>>>>   }
>>>>
>>>>   IMAGE_CMD_jffs2 = "mkfs.jffs2 --root=${IMAGE_ROOTFS} --faketime --output=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.jffs2 ${EXTRA_IMAGECMD}"
>>>> +
>>>>   IMAGE_CMD_cramfs = "mkcramfs ${IMAGE_ROOTFS} ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.cramfs ${EXTRA_IMAGECMD}"
>>>> +
>>>>   IMAGE_CMD_ext2 = "genext2fs -b $ROOTFS_SIZE -d ${IMAGE_ROOTFS} ${EXTRA_IMAGECMD} ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext2"
>>>>   IMAGE_CMD_ext2.gz () {
>>>>   	rm -rf ${DEPLOY_DIR_IMAGE}/tmp.gz&&  mkdir ${DEPLOY_DIR_IMAGE}/tmp.gz
>>>> -	genext2fs -b ${IMAGE_ROOTFS_SIZE} -d ${IMAGE_ROOTFS} ${EXTRA_IMAGECMD} ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext2
>>>> +	genext2fs -b $ROOTFS_SIZE -d ${IMAGE_ROOTFS} ${EXTRA_IMAGECMD} ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext2
>>>>   	gzip -f -9 ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext2
>>>>   	mv ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext2.gz ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext2.gz
>>>>   	rmdir ${DEPLOY_DIR_IMAGE}/tmp.gz
>>>>   }
>>>> +
>>>>   IMAGE_CMD_ext3 () {
>>>>   	genext2fs -b $ROOTFS_SIZE -d ${IMAGE_ROOTFS} ${EXTRA_IMAGECMD} ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext3
>>>>   	tune2fs -j ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext3
>>>>   }
>>>>   IMAGE_CMD_ext3.gz () {
>>>>   	rm -rf ${DEPLOY_DIR_IMAGE}/tmp.gz&&  mkdir ${DEPLOY_DIR_IMAGE}/tmp.gz
>>>> -	genext2fs -b ${IMAGE_ROOTFS_SIZE} -d ${IMAGE_ROOTFS} ${EXTRA_IMAGECMD} ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext3
>>>> +	genext2fs -b $ROOTFS_SIZE -d ${IMAGE_ROOTFS} ${EXTRA_IMAGECMD} ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext3
>>>>   	tune2fs -j ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext3
>>>>   	gzip -f -9 ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext3
>>>>   	mv ${DEPLOY_DIR_IMAGE}/tmp.gz/${IMAGE_NAME}.rootfs.ext3.gz ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.ext3.gz
>>>> diff --git a/meta/conf/distro/include/default-distrovars.inc b/meta/conf/distro/include/default-distrovars.inc
>>>> index 1aa45c8..4b68a0a 100644
>>>> --- a/meta/conf/distro/include/default-distrovars.inc
>>>> +++ b/meta/conf/distro/include/default-distrovars.inc
>>>> @@ -1,7 +1,5 @@
>>>>   QA_LOGFILE = "${TMPDIR}/qa.log"
>>>>
>>>> -IMAGE_ROOTFS_SIZE_ext2 ?= "131072"
>>>> -
>>>>   OEINCLUDELOGS ?= "yes"
>>>>   KERNEL_CONSOLE ?= "ttyS0"
>>>>
>>>> diff --git a/meta/conf/machine/include/qemu.inc b/meta/conf/machine/include/qemu.inc
>>>> index 4122a88..9ef242f 100644
>>>> --- a/meta/conf/machine/include/qemu.inc
>>>> +++ b/meta/conf/machine/include/qemu.inc
>>>> @@ -6,8 +6,6 @@ MACHINE_FEATURES = "kernel26 apm alsa pcmcia bluetooth irda usbgadget screen"
>>>>   IMAGE_FSTYPES ?= "tar.bz2 ext3"
>>>>
>>>>   ROOT_FLASH_SIZE = "280"
>>>> -IMAGE_ROOTFS_SIZE_ext2 ?= "280000"
>>>> -IMAGE_ROOTFS_SIZE_ext3 ?= "280000"
>>>>
>>>>   # Don't include kernels in standard images
>>>>   RDEPENDS_kernel-base = ""
>>>> diff --git a/meta/recipes-core/images/core-image-minimal-initramfs.bb b/meta/recipes-core/images/core-image-minimal-initramfs.bb
>>>> index 21aaa6c..3246d5c 100644
>>>> --- a/meta/recipes-core/images/core-image-minimal-initramfs.bb
>>>> +++ b/meta/recipes-core/images/core-image-minimal-initramfs.bb
>>>> @@ -8,3 +8,5 @@ IMAGE_LINGUAS = ""
>>>>   LICENSE = "MIT"
>>>>
>>>>   inherit core-image
>>>> +
>>>> +IMAGE_ROOTFS_SIZE = "8192"
>>>
>>> I'm not really sure about this, an initramfs that's the same size as a
>>> more fully featured rootfs?
>>>
>> That may be, then we need to increase the size slightly, but this will 
>> trigger the correct behavior of actual size * IMAGE_OVERHEAD_FACTOR, 
>> rather than the 64M which would be the default, this was to ensure it 
>> could get smaller.  I don't have a current initramfs size, I will build 
>> and verify.
>>
>>
>>>> diff --git a/meta/recipes-core/images/core-image-minimal.bb b/meta/recipes-core/images/core-image-minimal.bb
>>>> index aa00e67..743e121 100644
>>>> --- a/meta/recipes-core/images/core-image-minimal.bb
>>>> +++ b/meta/recipes-core/images/core-image-minimal.bb
>>>> @@ -9,5 +9,7 @@ LICENSE = "MIT"
>>>>
>>>>   inherit core-image
>>>>
>>>> +IMAGE_ROOTFS_SIZE = "8192"
>>>> +
>>>
>>> In your cover letter you stated that the minimal image is currently
>>> 9.9M, which means we *need* the overhead to contain the entire image
>>> contents. Correct? That seems a little unwise.
>>>
>> Right, that's currently, we want to see the image get smaller even, so 
>> the 8M is an appropriate setting.  Currently the actual ext3 image is 
>> 13M with 10M of contents.
>>
>> So are you suggested that the 8M size is unwise or the overhead, not 
>> sure I am catching your meaning here.
> 
> I'm just nervous about relying on the overhead, what if someone sets it
> lower and then the image doesn't fit?
> 
> Having the goal of a smaller minimal image is good but in my opinion we
> should adjust the rootfs size when the image is smaller, not before.

Every argument I've heard in favor of the IMAGE_OVERHEAD was centered
around ensuring there is enough space for the user to actually use the
system after it was installed and booted. Using this single metric to
try and both make up for oversized images and provide space for user
data seems like to cause maintenance issues going forward.

While our goal should be to reduce the image size, the default image
size in the recipes should default to the largest of the images built
for the supported machines. The overhead should be used strictly for
user data.

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel